Image sensors are semiconductor devices capable of converting electric signals into optical images. Image sensors may be classified into various types, including charge coupled device (CCD) type and complementary metal oxide semiconductor (CMOS) type. A CMOS type image sensor, i.e., referred to as CIS, may include pixels arranged in two dimensions. Each of the pixels may include a photodiode (PD), which converts incident light into an electric signal.
As semiconductor devices become more highly integrated, image sensors may likewise become highly integrated. Accordingly, the corresponding pixels may be scaled down, such that cross talk may frequently occur between pixels.